Answer:
$1300
Step-by-step explanation:
If each person paid $725 and four people paid the total amount for first month's rent, last month's rent and security deposit, the total amount paid is $725 x 4 = $2900
As each month's rent is $800, the first month's and last month's rent is $800 x 2 = $1600
Thus, the security deposit is $2900 - $1600 = $1300